The Poison Review

A case of acute valproic acid poisoning treated successfully with L-carnitine. Papaseit EP et al. Eur J Emerg Med 2012;19:57-8.

No abstract available

This short case report describes a 30-year-old man who presented with decreased mental status and increased ammonia level after an apparent acute overdose of valproic acid (VA). Interestingly, laboratory tests showed no evidence of hepatotoxicity. To make a short story even shorter, he was treated with supportive care and intravenous L-carnitine and got better. It is, of course, completely unclear what role if any carnitine had in bringing about the good outcome. Nevertheless, the authors jump right in and suggest that this case supports the hypothesis that L-carnitine is safe and effective treatment in VA overdose.

The use of L-carnitine to treat acute VA overdose has been long debated. Since it has few side effects, most authors recommend its use. Chronic therapy with VA induces carnitine deficiency, leading to hepatotoxicity and elevated serum ammonia levels. The theory is that acutely repleting carnitine will be beneficial in VA overdose. Although retrospective reviews have suggested that early treatment with IV L-carnitine is associated with improved outcomes in these patients, there have been no good studies showing establishing cause and effect. My own thinking about this has changed from “carnitine, schmarnitine” to “carnitine, why not?”

Goldfrank’s Toxicologic Emergencies (9th edition) states:

For patients with valproic acid-induced symptomatic hepatotoxicity or symptomatic hyperammonemia, IV L-carnitine should be administered.

This seems as reasonable an approach as any.

Related post:

Carnitine for acute valproic acid overdose? Who knows?